Expression of L-selectin (CD62L) and CD44 on Bovine Lymphocytes and WC1.1+ γδ T Cells under Stimulation with Staphylococcus aureus

The present study explored the expression of CD62L and CD44 by bovine peripheral blood mononuclear cells (PBMCs) and WC1.1+ γδ T cells under Staphylococcus aureus cell culture stimu-lation. In this study, peripheral blood cells were isolated from ten dairy cows and cocultured with S. aureus. Afterward, the γδ T cell subpopulation and the expression of CD44, CD62L and prolif-erative (Ki67+) cells were evaluated by flow cytometry. Our results showed that the percentages of proliferative PBMCs and WC1.1+ γδ T cells were higher when stimulated with S. aureus. The percentage of CD44+ cells increased in S. aureus-stimulated cultured PMBCs and WC1.1+ γδ T cells, as did the CD44 geometric mean fluorescence intensity (GMFI). The rate of CD62L cells did not differ among groups for either PBMCs or WC1.1+ γδ T cells. A higher GMFI of CD62L in prolif-erative PBMCs than nonproliferative PBMCs upon stimulation with S. aureus was detected, whereas no impact on the GMFI of CD62L was observed in WC1.1+ cells. In summary, our study identified that S. aureus was associated with high expression of CD44 in overall PBMCs and WC1.1+ γδ T cells, and they could generate memory WC1.1+ γδ T cells, preferably central memory cells.